1. Field of the Invention
The present invention relates to a handheld device and a power saving method therefor. More particularly, the present invention utilizes a light sensor to detect the change of ambient brightness in different receiver modes. Accordingly, the display status of the handheld device can be determined.
2. Description of the Related Art
Increasing the operation time has always been an important issue for users of handheld devices, such as mobile phones or PDAs, as well as for the industry. Not all of the components of a handheld device need to be powered on when the handheld device is in use. Therefore, shutting down certain functions or turning off certain components that the user is not using at proper times may help save some power.
Generally, the screen of a handheld device consumes quite much power. Therefore, the conventional handheld devices typically use the built-in software to set a predetermined time duration. When a handheld device has been idling for some time longer than the predetermined time duration, the handheld device will turn off the screen automatically to save power. However, the conventional handheld devices do not allow the screens to be automatically turned off while the user is answering a phone call or making an dialing call. The handheld device will not turn off the screen until a predetermined time duration is reached. It is known that the user does not need to use the screen while speaking with a handheld device. Thus, the conventional handheld devices may cause unnecessary power consumption, which leads to the decrease of operation time.
To overcome the above drawback, the present invention provides a handheld device and a power saving method therefor. This invention uses a light sensor for determining whether the user is holding the device close to the ear while answering or placing calls; based on the determination result, the handheld device can further shut down certain functions or turn off certain components that are not in use. Therefore, power consumption can be effectively reduced, and longer operation time can be achieved with a handheld device of this invention. There are a few handheld device products in the market that are capable of turning off screens while making calls. However, such products need to further integrate a cap sensor or proximity sensor to achieve the aforementioned objectives. The present invention only employs a light sensor for saving power and increasing battery lifetime. Thus, the present invention can also help reducing production cost.